Relation of Atrial Function to Ventricular Filling During Preload Reduction in Normal Subjects: Combined Analysis of Atrioventricular and Venous Flow Velocities

Background. Although pulsed Doppler echocardiography, particularly recordings of the transmitral and pulmonary venous flow (TMF and PVF, respectively) velocities, could recently serve as a useful tool in the evaluation of left ventricular (LV) diastolic function, the mechanisms underlying the relation of atrial function to ventricular filling are incompletely understood.Methods. We performed transthoracic and transesophageal pulsed Doppler echocardiography during lower body negative pressure (LBNP, -20 and -40 mm Hg) in 14 healthy volunteers, and assessed the changes in superior vena cava (SVC) flow, transtricuspid flow (TTF), TMF, and PVF velocity patterns during preload reduction.Results. During LBNP, there were no significant changes in heart rate and mean blood pressure. The LV end-diastolic and maximal left atrial dimensions were decreased, whereas there were no significant changes in percent LV fractional shortening. The peak early diastolic velocity (E) and the initial time-velocity integral between the onset and the time of peak flow velocity of the early diastolic filling (IEa) of the TTF and TMF velocities were decreased. The peak second systolic velocity (S2) of the SVC flow and PVF velocities, and time-velocity integral of the second systolic wave (IS2) of the PVF velocity were decreased. There was a positive correlation between the changing IEa (ΔIEa) of the TMF velocity and the changing IS2 (ΔIS2) of the PVF velocity during preload reduction. There were no significant changes in atrial systolic parameters of the TTF and TMF velocities.Conclusions. Atrial passive emptying contributes to the former-part of the early diastolic ventricular filling, particularly in the left heart side, in normal subjects.